Carburetor



1940- F. w. CLOEDY ET AL.

CARBURETOR Filed Jan. 6, 1938 a s Q m was? Patented Feb. 27, 1940 canmms'roa v Frederic Cloedy, St. Louis, and Harold A. Carlson, University City, Mo., assignors to Carter Carburetor Corporation, St. Louis, Mo., a corporation of Delaware Application January 6, 1938, Serial No. 183,604

1 Claim. (01. eta-s9) This invention relates to carburetors for internal combustion engines and consists particularly in novel means for stabilizing the fuel metering characteristics thereof.-

A well'known form of automotive carburetor utilizes a stepped or tapered metering pin associated with the main calibrated fuel metering orifice/in the fuel bowl in such a manner as to vary the effective cross sectional area of the i orifice to supply a richer or leaner fuel and air mixture according to the demands 'of the engine. This metering pin may be moved axially with the throttle valve so' as to reduce the restricting effect upon the metering orifice as the r I! throttle valve is opened, or it may be controlled by a suction device in a manner to increase the open portion of the metering orifice when the suction in the mixture conduit drops. It has been found that the concentricity or eccentricity of the me- I tering pin relative to the metering orifice has a substantial eifect upon the fuel metered therethrough and, accordingly, means should be provided for maintaining the relative position of the pin substantially uniform in this respect. One

means of accomplishing this result is illustrated andclaimed in a United States Patent No. 1,961,747, issued in the name of William M. Ewart. I

One object of the present invention is to provide novel means for maintaining the fuel metering pin in a'stable relationship with its metering orifice. Another object is to provide means for stabilizing the relative position of 'a' fuel metering 8 pin, which means is particularly adaptable for use in carburetors in which the pin is controlled by a suction piston or other suction controlled means. u

These objects and other more detailed objects 40 hereafter appearing are attained substantially by the structure illustrated in the accompanying drawing in which Fig. 1 is a side view partly sectioned of a carburetor embodying the invention. I as Fig. 2 is a detail horizontal section taken on the corresponding section line of Fig. 1.

Fig. 3 is a detail vertical section taken substantially on the corresponding section line of Fig. 1. Fig. 4 is a perspective view showing a part of 50 the structure in Fig. 1.

Fig. 5 is a detail view, partly sectioned and partly in perspective, illustrating a. modification and Fig. 6 is a perspective view showing a modified detailasinFigJ.

' in the fuel bowl.

on air inlet horn Ia slidably receives a closely 50 The carburetor in Fig. 1 comprises a down draft mixture conduit including an air. inlet horn I, venturis'Z, and outlet portion 3, flanged as at l for attachment to the intake manifold (not shown) of an associated internal combustion engine. J A throttle valve 5 is. pivotally mounted near the outlet portion of the mixture conduit and pr vlded with any suitable manual control means -(not shown) Adjacent the mixture conduit is a bowl 6 within which fuel is maintained at a substantially constant level :r-a: by needle valve mechanism 1, controlled by float 8. Fuel is supplied to the mixture conduit through a main nozzle 9 opening into the throat portion of the smallest venturi 2 and communicating with the II fuel bowl through a calibrated metering orifice member in. Fuel for idling and low speed operation is supplied through a passage, shown in part at H, opening into the mixture conduit through a port I! adjacent the edge of the throttle valve 343 when closed j Formedii n' the wall of the mixture conduit is a cylinder or chamber l3 communicating through a passage 14 with opening 15 into themixture conduit posterior to the throttle. slidable within chamber I3 is a. piston it having an elongated rod ll projecting thereabove through cover l8 of the fuel bowl and having at its upper portion a laterally offset arm 19 pinned as at 20 to a metering pin 2| having a stepped lower portion 22 extending into metering orifice member. I0 for varying the effective cross-sectional area thereof. A pair of ribs or wings 23 project laterally from the portion of piston rod ll within chamber 13 and are slidable within slots 24 (Fig. 2) to prevent rotation of piston rod l1 and also guide the rod and pin -2l in their longitudinal movements. Due to the lateral offsetting of the actuating rod I! from the metering pin, this guiding structure has the effect of maintaining the metering pin substantially uniformly positioned transversely of the metering orifice.

In Figs. 5 and 6, elongated piston rod member I la projecting above suction controlled piston 18a has a pair of laterally onset arms 25 for carrying a pair of metering pins 28, this arrangement being adapted foruse in a dual carburetor having a pair of calibrated metering orifice members Guiding structure '26 formed fitting portion 21 on the upper part of the piston rod for preventing rotation of the rod and maintaining the metering pins uniformly positioned relative to the metering orifices.

In both forms, aspring 26 in the suction chamg5 The general features of the carburetor shown,

I -with the exception of the fuel metering mechanism, are well known in the art and do not constitute the present invention. The exclusive use of all modifications as come within the scope of the appended claim is contemplated.

We claim:

In "a carburetor, a mixing conduit, a part having a calibrated fuel metering orificespaced transversely from the wall of said conduit, aguide opening co-axially arranged with respect to said metering orifice, a metering pin having a reduced lower extremity normally extending into said orifice, a cylindrical chamber in the wall of said conduit communicating at its lower portion with suction in said conduit, a piston in said chamber, a spring arranged in said cylindrical chamber between the piston and the lower end of said chamber, a piston rod' projecting upwardly from said piston and having a laterally oflset portion forming a mounting for said metering pin for moving the same parallel to the axis of said cylinder to vary the efl'ective cross-sectional area 10 of said orifice,- non-circular guide means on the wall of said conduit adjacent said piston rod, said piston rod having a non-circular elongated portion extending laterally therefrom, and closely fitting said guide means to prevent rotation of 15 the rod so as to maintain uniform positioning of said pin mounting transversely of the axis of said orifice, whereby the pin is restrained at all times from misalignment with said orifice due to pivotal movement with respect to the wall forming the guide opening.

. F; W. CLOEDY.

H. A. CARL-SON. 

